This invention relates to a method and apparatus for randomizing multiple yarn strands. In the particular embodiment dislosed in this application, the randomizing apparatus shown comprises a modified winder of the type which includes an air jet entangling station. However, the invention has application on other types of yarn processing equipment as well.
Yarn patterning is a common problem in yarn processing operations. Generally, the problem results from minute differences in yarns being processed, and the tendency for those yarns to behave in a predictable manner based upon their slightly different characteristics relative to one another.
Yarn patterning manifests itself in downstream processes in dyeing variations, streaks, yarns repeating on the surface in knitted or woven fabrics and in carpets. The problem is a particularly difficult one to correct because the problem and, of course, the success of any attempted correction, is not apparent until later processes. It is practically impossible to create absolutely identical yarns or yarn strands.
For example, yarns tend to pass over guides and rollers in a consistent manner, especially after wear has grooved the guides or rollers. In air jet texturing, patterning becomes more of a problem as tension in the process is reduced. If the air jet is a type which does not twist the yarn, the air stream tends to catch the same end of yarn, entangling it in a repeating manner. This shows up in a carpet as a streak or an obviously repeating yarn.
Because it is often desirable to reduce tension for other reasons, yarn patterning tends to become worse and can become so serious that fabric or carpet manufactured from the yarn is not first quality.
It has been found that a vortex can be used to eliminate patterning when combining a plurality of yarns in a process such as winding. Vortex devices have heretofore been used for filament yarn handling as in open end and vortex spinning, where the vortex is used as a twist insertion means.